Effects of Magnesium and Calcium on the Oxygenation Reaction of Erythrocruorin from the Marine Polychaete Arenicola marina and the Terrestrial Oligochaete Lumbricus terrestris

Ochiai, Takehiko; Weber, Roy E.

doi:10.2108/zsj.19.995

Cited by 14 publications

(6 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In addition to the linker chains, ions play a key role in stabilizing the molecule. Calcium is significant for the stabilization of LtHb [37], while magnesium is more important for ArHb than calcium [38]. As demonstrated by the present studies, it appears that the positive redox potentials of LtHb and ArHb serve as the basis for their extraordinary resistance to heme oxidation.…”

Section: Discussionmentioning

confidence: 51%

Acellular Invertebrate Hemoglobins as Model Therapeutic Oxygen Carriers: Unique Redox Potentials

Harrington

Kobayashi

Dorman

et al. 2007

Artificial Cells, Blood Substitutes, and Biotechnology

View full text Add to dashboard Cite

Natural acellular polymeric hemoglobins (Hb) provide oxygen transport and delivery within many terrestrial and marine invertebrate organisms. It has been our premise that these natural acellular Hbs may serve as models of therapeutic hemoglobin-based oxygen carriers (HBOC). Our attention has focused on the acellular Hb from the terrestrial invertebrate, Lumbricus terrestris (Lt), which possesses a unique hierarchical structure and a unique ability to function extracellularly without oxidative damage. Lumbricus Hb and Arenicola Hb are resistant to autoxidation, chemical oxidation by potassium ferricyanide, and have little or no capacity to transfer electrons to Fe(+3)-complexes at 37 degrees C. An understanding of how these invertebrate acellular oxygen carriers maintain their structural integrity and redox stability in vivo is vital for the design of a safe and effective red cell substitute. We report here a positive redox potential for these giant hemoglobins that may lie at the basis for its resistance to oxidation.

show abstract

Section: Discussionmentioning

confidence: 51%

Acellular Invertebrate Hemoglobins as Model Therapeutic Oxygen Carriers: Unique Redox Potentials

Harrington

Kobayashi

Dorman

et al. 2007

Artificial Cells, Blood Substitutes, and Biotechnology

View full text Add to dashboard Cite

show abstract

“…12 It shows cooperative oxygen binding, with maximum Hill coefficients above 4, and strong sensitivity to divalent cations and protons. 13 Mass spectrometry experiments have identified eight distinct hemoglobin subunits, five of which have now been sequenced and two distinct linker subunits, one of which has been sequenced. 14,15 As in the case of Lumbricus erythrocruorin, dissociation reveals both disulfide linked hemoglobin trimers and hemoglobin subunits not disulfide linked to other subunits.…”

Section: Introductionmentioning

confidence: 99%

Low Resolution Crystal Structure of Arenicola Erythrocruorin: Influence of Coiled Coils on the Architecture of a Megadalton Respiratory Protein

Royer

Omartian

Knapp

2007

Journal of Molecular Biology

View full text Add to dashboard Cite

Annelid erythrocruorins are extracellular respiratory complexes assembled from 180 subunits into hexagonal bilayers. Cryo-electron microscopic experiments have identified two different architectural classes. In one, designated type I, the vertices of the two hexagonal layers are partially staggered, with one hexagonal layer rotated by about 16 degrees relative to the other layer, whereas in the other class, termed type II, the vertices are essentially eclipsed. We report here the first crystal structure of a type II erythrocruorin, that from Arenicola marina, at 6.2 A resolution. The structure reveals the presence of long continuous triple-stranded coiled-coil "spokes" projecting towards the molecular center from each one-twelfth unit; interdigitation of these spokes provides the only contacts between the two hexagonal layers of the complex. This arrangement contrasts with that of a type I erythrocruorin from Lumbricus terrestris in which the spokes are broken into two triple-stranded coiled coils with a disjointed connection. The disjointed connection allows formation of a more compact structure in the type I architecture, with the two hexagonal layers closer together and additional extensive contacts between the layers. Comparison of sequences of the coiled-coil regions of various linker subunits shows that the linker subunits from type II erythrocruorins possess continuous heptad repeats, whereas a sequence gap places these repeats out of register in the type I linker subunits, consistent with a disjointed coiled-coil arrangement.

show abstract

“…Mg 2þ , Li þ , Br À (400 mmol/mL) were supposed to substitute the physiological analogues (such as Ca 2þ , Na þ , and Cl À , respectively) and influence their effects involved in signal transduction. The concentrations of Mg 2þ was 100-fold higher in this experiment than the physiological concentrations (2.0-4.0 mmol) (Ochiai and Weber, 2002.). Extracellular magnesium ions inhibit the Na-Ca antiport in a competitive manner with calcium ions (Bara et al,'93).…”

Section: Discussionmentioning

confidence: 77%

Longitudinal in vivo MR imaging of live earthworms

et al. 2014

View full text Add to dashboard Cite

Earthworm (Oligochaeta, Lumbricidae) species are used widely in eco-toxicological tests especially with contaminated soils. These long-term tests are reliable, but a high sample size is needed. Magnetic resonance imaging (MRI) can produce fast, robust, sensitive, and longitudinal morphological results using a small sample size. Performing longitudinal in vivo examinations of earthworms using MRI requires the need for anesthetics to completely avoid earthworm's moving. Our goal was to develop a simple and non-invasive method to anesthetize earthworms for in vivo longitudinal imaging studies. We investigated a number of different anesthesia methods and found that propan-2-ol and its vapor was optimal. We used a commercial sequential nanoScan® PET/MRI system (Mediso Ltd, Hungary, Budapest) to explore feasibility of MR imaging in immobilized earthworms. It was possible to visualize via micro MRI the brain, gastrointestinal tract, seminal vesicles, calciferous gland (Morren gland), and main blood vessels of the circulatory system. Our findings show the possibilities to examine changes in morphology using MRI of certain organs using a reversible, long-term immobilization method.

show abstract

Effects of Magnesium and Calcium on the Oxygenation Reaction of Erythrocruorin from the Marine Polychaete Arenicola marina and the Terrestrial Oligochaete Lumbricus terrestris

Cited by 14 publications

References 35 publications

Acellular Invertebrate Hemoglobins as Model Therapeutic Oxygen Carriers: Unique Redox Potentials

Acellular Invertebrate Hemoglobins as Model Therapeutic Oxygen Carriers: Unique Redox Potentials

Low Resolution Crystal Structure of Arenicola Erythrocruorin: Influence of Coiled Coils on the Architecture of a Megadalton Respiratory Protein

Longitudinal in vivo MR imaging of live earthworms

Contact Info

Product

Resources

About